Forgotten Title Fl has red hair and a son with red hair just like her

I'm looking for a manhwa i hope someone can help me with it.
Fl has red hair and grey or green eyes(kinda forgot)while ml has black hair and gold eyes. If i remember correctly ml went to fl family to kill them but fl already killed them since they treat her badly? Then ml took fl and took care of her then fl got pregnant but ml doesnt want the child because he believe that the child is a monster like him?(I think it has something to do with ml's blood or genes) So fl runs away and hide from ml. Fast forward, ml is looking for fl then found a child who has red hair and grey/green eyes like fl and turns out its the son of fl. Ml didnt think that the child is his son because all the children born from ml's family has black hair and gold eyes(i think?)but he soon found that the child is his because of a pendant with his portrait inside?

 

An Unexpected Engagement?

 

Oooh. I found the LN for An Unexpected Engagement, but it had been taken down. I didn't know there was a Manhwa of it (I didn't think to look). It sounded really good, so I'm going to have to look for that now. Thanks for the info!

 

Yes! this is the one im looking for. Thank you, its been bothering me for a while since i cant remember the title